CAV Ice Posted September 15, 2021 Report Share Posted September 15, 2021 Have a Columbia 400 with a nose wheel shimmy. It is very light below 20kts and increases to moderate between 25 and 28kts. After 30kts it stops. Tire is balanced, bearings are good, strut is serviced and I'm out of ideas on what to do to stop this shimmy. Any thoughts are much appreciated! Thanks! Quote Link to comment Share on other sites More sharing options...
carusoam Posted September 16, 2021 Report Share Posted September 16, 2021 7 hours ago, CAV Ice said: Have a Columbia 400 with a nose wheel shimmy. It is very light below 20kts and increases to moderate between 25 and 28kts. After 30kts it stops. Tire is balanced, bearings are good, strut is serviced and I'm out of ideas on what to do to stop this shimmy. Any thoughts are much appreciated! Thanks! CAV, We have a well respected Service center that wrote how to solve this problem for Mooneys… The title of the bulletin is called ‘the eight second ride’ (a bull riding reference) See if you can find the Don Maxwell Aviation site…. Where his writings are often available… Briefly, The nose wheel is often responsible for shimmy for a couple of reasons…. Wear and proper over center alignment… Do a search on the word plumb bob around here… there will be a picture showing the alignment of the nose wheel structure and the nose wheel… For Mooneys with several thousand hours on them… OHing the nose gear is a short cut to getting back on the centerline… Thanks for all your help over the years… hope this is helpful for you. PP thoughts only, not a mechanic… Best regards, -a- 1 Quote Link to comment Share on other sites More sharing options...
LANCECASPER Posted September 19, 2021 Report Share Posted September 19, 2021 On 9/15/2021 at 3:56 PM, CAV Ice said: Have a Columbia 400 with a nose wheel shimmy. It is very light below 20kts and increases to moderate between 25 and 28kts. After 30kts it stops. Tire is balanced, bearings are good, strut is serviced and I'm out of ideas on what to do to stop this shimmy. Any thoughts are much appreciated! Thanks! 18 knots is about 20 mph, school zone speed in a car. If the shimmy is hardly noticeable below 20, I’d taxi below 20. How is it at 10 (running speed) or a 5 (very brisk walking speed)? I can’t imagine taxiing a small airplane at 35 mph (30 knots). If you hit a pothole or bump at that speed a prop strike is almost a given. Quote Link to comment Share on other sites More sharing options...
Davidv Posted September 19, 2021 Report Share Posted September 19, 2021 1 hour ago, LANCECASPER said: 18 knots is about 20 mph, school zone speed in a car. If the shimmy is hardly noticeable below 20, I’d taxi below 20. How is it at 10 (running speed) or a 5 (very brisk walking speed)? I can’t imagine taxiing a small airplane at 35 mph (30 knots). If you hit a pothole or bump at that speed a prop strike is almost a given. I agree on the taxi speed but he may be getting it on the roll out after landing. This has happened to me a few times. It occurs very rarely but not fun when it does. 1 Quote Link to comment Share on other sites More sharing options...
Greg Ellis Posted September 20, 2021 Report Share Posted September 20, 2021 On 9/15/2021 at 3:56 PM, CAV Ice said: Have a Columbia 400 with a nose wheel shimmy. It is very light below 20kts and increases to moderate between 25 and 28kts. After 30kts it stops. Tire is balanced, bearings are good, strut is serviced and I'm out of ideas on what to do to stop this shimmy. Any thoughts are much appreciated! Thanks! I think the most obvious way to get rid of the nose wheel shimmy on your Columbia 400 is to sell it and buy a Mooney....problem solved. 3 Quote Link to comment Share on other sites More sharing options...
StevenL757 Posted September 20, 2021 Report Share Posted September 20, 2021 14 minutes ago, Greg Ellis said: I think the most obvious way to get rid of the nose wheel shimmy on your Columbia 400 is to sell it and buy a Mooney....problem solved. ...or a Citation M2. Quote Link to comment Share on other sites More sharing options...
WaynePierce Posted September 20, 2021 Report Share Posted September 20, 2021 Here is a link with all of Don Maxwell's articles that he sent on a post I started on The Eight Second Ride... https://web.archive.org/web/20180718211708/http://donmaxwell.com/publications/ 1 Quote Link to comment Share on other sites More sharing options...
A64Pilot Posted September 20, 2021 Report Share Posted September 20, 2021 While I know nothing about a Columbia, if it’s one of the nose wheels that aren’t steerable like a Cirrus or a Tiger etc, they often have a friction adjustment, if the friction is too lose, they will shimmy. Van’s RV “A” model aircraft can wheel shimmy so bad that it collapses and has killed people, so treat nose wheel shimmy seriously. 1 Quote Link to comment Share on other sites More sharing options...
GeeBee Posted September 21, 2021 Report Share Posted September 21, 2021 The one thing I notice about the Columbia design is there is not a lot of caster in the nose wheel. With a single tire not a lot of Marstand effect on the fork. I would change the tire and tube. True the rim while doing it as it could be bent. Check the axle for true, then verify the entire assembly runs true on the axle both laterally and radially. If all is good there I would turn my attention to the strut play within the tube. With as little caster, a little bit of play could create a lot of havoc down lower. 1 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.